Glioblastoma (GBM) is one of the most malignant types of primary brain cancers with currently no curative modalities available. Hence, the development of effective therapeutics is urgently needed. Emerging evidence suggests that a rare subset of cancer cells, so-called cancer stem cells (CSC) or cancer-initiating cells (CIC), drives and sustains tumor growth. GBM, one of the most malignant types of primary brain cancers, has been reported to contain CSCs. Discovery of CSCs in GBM provides insight into its biology as well as strategies against the neoplasm. CSCs may represent the source of recurrence of GBM. In order to prevent tumor recurrence, CSCs should be destroyed specifically. It is therefore crucial to develop therapeutic strategies against CSCs.